On November 4, 1998, Keiryo Mizuno and his wife Midori Mizuno died in a deliberately set fire at their Daly City apartment building on Poncetta Drive. The couple lived in unit #230; both succumbed to smoke inhalation before rescuers could reach them. The blaze has been classified as arson, and the deaths are treated as homicides caused by that deliberate fire.

The case remains unsolved and no arrests have been announced. Investigators have periodically reexamined the file and at times sought new leads, but the identity of the arsonist is still unknown. If anyone knew the Mizunos, lived in that building, or has information about the fire on November 4, 1998, contact the Daly City investigators handling the case.